The present invention generally relates to apparatuses and methods employed in the home for laundering clothing and fabrics. More particularly, it relates to a new and improved method and apparatus for home laundering of a fabric load using a wash liquor comprising a multi-phase mixture of a substantially inert working fluid and at least one washing additive.
In the Specification and Claims, the terms xe2x80x9csubstantially non-reactivexe2x80x9d or xe2x80x9csubstantially inertxe2x80x9d when used to describe a component of a wash liquor or washing fluid, means a non-solvent, non-detersive fluid that under ordinary or normal washing conditions, e.g. at pressures of xe2x88x9210 to 50 atmospheres and temperatures of from about 10xc2x0 to about 45xc2x0 C., does not appreciably react with the fibers of the fabric load being cleaned, the stains and soils on the fabric load, or the washing additives combined with the component to form the wash liquor.
Home laundering of fabrics is usually performed in an automatic washing machine and occasionally by hand. These methods employ water as the major component of the washing fluid. Cleaning additives such as detergents, enzymes, bleaches and fabric softeners are added and mixed with the water at appropriate stages of the wash cycle to provide cleaning, whitening, softening and the like.
Although improvements in automatic washing machines and in cleaning agent formulations are steadily being made, as a general rule, conventional home laundering methods consume considerable amounts of water, energy and time. Water-based methods are not suitable for some natural fiber fabrics, such as silks, woolens and linens, so that whole classes of garments and fabrics cannot be home laundered, but instead, must be sent out for professional dry cleaning. During water washing, the clothes become saturated with water and some fibers swell and absorb water. After washing, the water must be removed from the clothes. Typically, this is performed in a two-step process including a hard spin cycle in the washer and a full drying cycle in an automatic dryer. The hard spin cycles tend to cause wrinkling which is not wanted. Even after spinning, drying cycle times are undesirably long.
Non-aqueous washing methods employed outside the home are known, but for various reasons, these methods are not suitable for home use. Generally, the non-aqueous washing methods to date employ substitute solvents in the washing fluid for the water used in home laundering.
Conventional dry cleaning methods have employed halogenated hydrocarbon solvents as a major component of a wash liquor. The most commonly used halogenated hydrocarbon solvents used for dry cleaning are perchloroethylene, 1,1,1-trichloroethane and CFC-113. These solvents are ozone depleting and their use is now controlled for environmental reasons. Moreover, many of these solvents are suspected carcinogens that would require the use of a nitrogen blanket. Accordingly, these dry cleaning solvents cannot be used in the home.
Alternative dry cleaning methods employed petroleum-based or Stoddard solvents in place of the halogenated hydrocarbon solvents. The petroleum-based solvents are inflammable and smog-producing. Accordingly, their commercial use is problematic and use of these materials in the home is out of the question. U.S. Pat. No. 5,498,266 describes a method using petroleum-based solvents wherein perfluorocarbon vapors are admixed with petroleum solvent vapors to remove the solvents from the fabrics and provide improvements in safety by reducing the likelihood of ignition or explosion of the vapors.
A further non-aqueous solvent based washing method employs liquid or supercritical carbon dioxide solvent as a washing liquid. As described in U.S. Pat. No. 5,467,492, highly pressurized vessels are required to perform this washing method. In accordance with these methods, pressures of about 500 to 1000 psi are required. Pressures of up to about 30 psi are approved for use in the home. The high pressure conditions employed in the carbon dioxide create safety hazards that make them unsuitable for residential use.
Various perfluorocarbon materials have been employed alone or in combination with cleaning additives for washing printed circuit boards and other electrical substrates, as described for example in U.S. Pat. No. 5,503,681. Spray cleaning of rigid substrates is very different from laundering soft fabric loads. Moreover, cleaning of electrical substrates is performed in high technology manufacturing facilities employing a multi-stage apparatus which is not readily adapted for home use.
Accordingly, to overcome the disadvantages of prior art home laundering methods, it is an object of the present invention to provide a new and improved method and apparatus for laundering a fabric load in the home employing a safe and effective, environmentally-friendly, nonaqueous wash liquor.
It is another object of the present invention to provide a new and improved apparatus for laundering a fabric load in the home, which is safe and effective for a broad range of fabric types, including natural fiber fabrics, such as woolens, linens and silks.
It is a further object of the present invention to provide a new and improved home laundering method and apparatus which consumes less water, time and energy than conventional water-based home laundering machines and methods.
It is still another object of the present invention to provide a new and improved dry to dry home laundering method and apparatus requiring less handling by the home user.
It is a further object of the present invention to provide a new and improved home dry to dry laundering method and apparatus which provides safe and effective fabric cleaning without introducing wrinkling.
In accordance with these and other objects, the present invention provides new and improved methods and apparatuses for laundering a fabric load in the home. In an embodiment, a method for laundering a fabric load is provided comprising the steps of:
disposing a fabric load in a wash container;
delivering a wash liquor to the fabric load, said wash liquor comprising a substantially non-reactive, non-aqueous, non-oleophilic, apolar working fluid and at least one washing additive;
applying mechanical energy to provide relative movement between said fabric load and said wash liquor for a time sufficient to provide fabric cleaning; and
thereafter, substantially removing said wash liquor from said fabric load.
In a preferred embodiment, the working fluid is a liquid under washing conditions and has a density of greater than 1.0. The working fluid has a surface tension of less than or equal to 35 dynes/cm2. The oil solvency of the working fluid should be greater than water without being oleophilic. Preferably, the working fluid has an oil solvency as measured by KB value of less than or equal to 30. The working fluid, also has a solubility in water of less than about 10%. The viscosity of the working fluid is less than the viscosity of water under ordinary washing conditions. The working fluid has a pH of from about 6.0 to about 8.0. Moreover, the working fluid has a vapor pressure less than the vapor pressure of water and has a flash point of greater than or equal to 145xc2x0 C. The working fluid is substantially non-reactive under washing conditions with fabrics in the fabric load, with the additives present in the at least one washing additive and with oily soils and water soluble soils in the fabric load.
The working fluid is substantially non-swelling to natural fabrics present in the fabric load.
In an embodiment, the working fluid is a fluorine-containing compound selected from the group consisting of: perfluorocarbons, hydrofluoroethers, fluorinated hydrocarbons and fluoroinerts. Preferably, the working fluid comprises a compound having the formula:
(CF3 (CF2)n)3 N 
wherein n is an integer of from 4 to 20.
In an embodiment, the at least one washing additive may be selected from the group consisting of: surfactants, enzymes, bleaches, ozone, ultraviolet light, hydrophobic solvents, hydrophilic solvents, deodorizers, fragrances, antistatic agents and anti-stain agents. Mixtures of any of these washing additives may be used. A number of washing additives may be individually mixed with working fluid and these mixtures may be sequentially contacted with the fabric load in any desired order.
In an embodiment relative movement between the fabric load and wash liquor is provided by moving the wash container in a manner which moves the fabric load with respect to the wash liquor. Relative movement may be provided by rotating the wash container about an axis, horizontal or otherwise, or by rotating the wash container about a vertical axis. Relative movement may be provided by nutating the wash container about a vertical axis. Relative movement may also be provided by pumping the wash liquor from the wash container and respraying the wash liquor into the wash container, as well as, by high pressure jetting of the wash liquor into the wash container. Vibratory shaking of the wash container may also be used to provide relative movement. Relative movement may be provided by exposing the wash container to ultra-sonic irradiation. Relative movement may also be provided by moving an agitator within the wash container relative to the wash container, or by reciprocally partially rotating the wash container with respect to stator blades mounted in the wash container.
A major advantage provided by the present invention is that it conserves time, water and energy.
Another advantage provided by the present invention is that a dryer is not required, saving cost, energy and floor space.
A further advantage provided by the present invention is that the preferred apparatus does not employ a hard spin cycle and eliminates the need for a dryer so that home laundering methods and apparatus are provided which are less noisy.
Still another advantage provided by the present invention is that less sorting, transferring and handling of the fabric load is required by the homeowner.
A further advantage provided by the present invention is that home laundering in accordance with the invention is substantially non-wrinkling so that no ironing is needed.
Still another advantage provided by the present invention is that because the wash liquor is non-wetting to the fabric load, no hard spin cycle is required, which in turn permits a washer to be provided which does not need a suspension system, thereby reducing cost, weight and energy.
A further advantage provided by the present invention is that effective cleaning of wool, silk and linen in the home is provided for the first time.